Atmospheric Pollution: Conclusions

In: Health

29 Nov 2014

The role of early childhood illnesses also was featured in a study of 18-year-olds brought up in two contrasting areas, London and a relatively pollution-free new town. Results of a logistic regression analysis of findings on the prevalence of respiratory symptoms (Table 4) showed that after smoking, a history of early respiratory illnesses (bronchitis, asthma, pneumonia, pleurisy) appeared to be the most important factor in relation to symptoms in adolescence. Beyond that, area of residence, with the implied differences in exposure to urban air pollution did not have much effect, but individual exposures, whether to outdoor or indoor pollutants could have contributed to the contrasts in respiratory illnesses.

The picture presented by a wide variety of studies, might be fitted into a general scheme as in Figure 2, showing an interplay between air pollution infections and smoking in the development and exacerbation of CAD. While there is little doubt that reduction of cigarette smoking would have the most profound beneficial effect, particular attention might also be given to respiratory infections during childhood. Prompt and effective treatment could reduce risks of longer-term damage to the respiratory system, and several aspects of the domestic environment, including dampness in the home and overcrowding, with attendant risks of crossinfection, may affect the incidence and severity of respiratory illnesses, but amid all these factors, air pollution is an exacerbating influence. All practical steps need to be taken to reduce not merely environmental levels of pollutants, such as smoke and sulfur dioxide, but also the exposure of individuals to these and other pollutants, concentrating especially on the young. read only

Conclusions
Considering these points in conjunction with findings reported in accompanying papers leads to the following conclusions:
1. In areas that have in the past been heavily polluted by emissions from the burning of coal or heavy oil, there is evidence of increased morbidity and mortality from CAD and exacerbations of respiratory illness at times of peak pollution.
2. In most developed countries, control of such emissions, applied both to domestic and industrial sources, has by now rendered these effects of minor importance compared with other factors.
3. Remaining problems are more likely to be associated with the microenvironment of the individual than the general outside air. In developing countries exposure to fumes from unflued cooking sources indoors presents special hazards.
4. Particular care is required to avoid the exposure of young children to high levels of pollution, whether of outdoor or indoor origin. Not only are there links between such exposures and the occurrences of respiratory illnesses, but these early experiences also contribute to the development of CAD in later life.
5. Cigarette smoking provides, for the smoker, the most intense exposures to pollution of any kind, and it can contribute appreciably to the exposure of others indoors. Measures to deter young people from taking up smoking and to encourage existing smokers to give up offer the greatest opportunities for reducing the prevalence of CAD.
Table 4—1957 Birth Cohort: Logistic Model: Increase in % Odds of Having Any One or More Respiratory Symptom at age 18 in Relation to Principal Factors Examined

Factor Increase in Odds, %
Smoking (No/Yes) 35
History of respiratory illness (No/Yes) 27
Area of residence (Crawley/London) 10
Sex (M/F) 5
Parental social class (upper/lower) 3

 

Figure 2. Respiratory infections, air pollution, and other factors in the development of chronic airways disease.

Figure 2. Respiratory infections, air pollution, and other factors in the development of chronic airways disease.


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